Issue No 7, January 1997.

NOTICE: Hard copies of the Australian New Crops Newsletter are available from the publisher, Dr Rob Fletcher. Details of availability are included in the Advice on Publications Available.

7.2 Development of the Williames Hi-Tech International Tea Harvester

Williames Hi-Tech International (WHTI) is a mechanical engineering company based in Warragul, Victoria, specialising in the design and manufacture of horticultural and agricultural equipment.

During a visit to Papua New Guinea in 1978, Geoff Williames was exposed to a number of problems with the tea industry in the highlands, namely, the lack of competitiveness with coffee, the unreliability of labour and the difficulties associated with co ntrolling tea quality.

This visit led to the elaboration of a performance-driven contract with W.R. Carpenters, a plantation owner in PNG, for Geoff Williames (Aust.) Pty Ltd (as WHTI was then known) to design and develop a mechanical tea harvester.

The first harvester, developed in 1979, was based on the Larson-Versa Trac, a very high clearance tractor made in Canada. This tractor straddled the rows of tea bushes.

The tea harvesting attachment, suspended over the bushes, consisted of a reciprocating cutter bar, vacuum chute, leaf separator, vacuum fans and collection bin. Tea cut from the top of the bushes was sucked up a chute, through a leaf separator and into a collection bin.

Within six months from when its development commenced, the first harvester was undertaking trials in PNG, where it harvested 6 acres (2.4 hectares) per hour, and was retained by Carpenters.

The next model built was based on a Ford 5000 tractor. This model, as well as offering greater power, had more readily available parts. This tractor was extensively modified to increase its ground clearance. A bag-carrying frame was included as an opti on.

Due to the instability of wheeled harvesters, which caused dipping of the cutter bar into the maintenance foliage whenever a wheel entered a pot-hole, WHTI decided to use a tracked system for the tea-harvester.

Initially, a steel-tracked system was considered, but suffered the disadvantage of being too heavy, and not sufficiently fast to be able to run at the speeds required for harvesting.

Caterpillar were contacted and advised against using a steel track due to the high wear that could be expected at tea harvesting speeds. WHTI then undertook development of its own track system, consisting of a set of looped cables encapsulated in a rub ber belt to which were attached steel cleats.

The first belt to be produced worked very well, and the tracked harvester offered superior cutting performance to wheeled vehicles.

To increase the life of the belt, polyurethane was seen as a viable alternative to rubber. A batching plant was built and the first successful polyurethane belt manufactured and tested. With a polyurethane belt, the silent track, which had a 90 tonne b reaking strain, demonstrated excellent reliability.

Development of the tea harvesting attachment had also continued, to include a rotary helix cutter bar, and a new bagging system. The rotary cutter bar made the machine more compact, as well as giving a more even and cleaner cut.

The new model tea harvester, called the WHTI T5000, performed extremely well, offering substantial savings to growers when they switched to mechanical harvesting. With an adjustable cut up to 12' (3.6 m) wide, the T5000 harvester was able to harvest up to four hectares per hour.

The T5000 has been sold in Papua New Guinea, Uganda, Malaysia, India and Mozambique.

Prompted by growers' requirements for a lighter-weight machine, development of the T3000 commenced.

The new harvester incorporated a simpler ducting system and a bulk bin. An extreme-duty undercarriage was developed, incorporating Caterpillar components and Rexroth hydraulic motors, increasing the load-bearing capacity of the track. The T3000 has bee n sold in Asia.

Development of the tea harvester models is continuing under a syndicated R&D grant from the Australian government.

The tea harvester is one example of the development of agricultural machinery by Williames' over the last 28 years.

Other agricultural machinery developments have included:

• a chopper plough for the one-pass removal of stumps from freshly cleared land (used on clear-felled pine slash to prepare the land for replanting);
• a range of horticultural nursery-filling and seeding machines;
• field transplanting machines for the agricultural industry and mechanical harvesting machines for crops as diverse as boronia, pyrethrum and tea.

The development of the tea-harvester illustrates many of the factors needed to successfully design and manufacture new agricultural machinery.

The first tea harvester was developed to solve a number of the problems faced by tea growers in Papua New Guinea. It was developed in six months, and gave PNG tea growers who adopted mechanical harvesters a significant economic advantage.

Without the "real world" demands of the tea industry, the tea harvester could have been developed, but not sold.

The tea harvester was initially developed under a performance-driven contract between Williames' and W.R. Carpenter, on the basis that development costs were covered by Carpenters, but the final payment was only made once the harvester performed to the specifications laid out in the contract.

Performance-Driven Design Development and Financing is an excellent way of satisfying the needs of both the investor and the innovator. The development of new technology is both expensive and risky.

By focusing on clearly spelling out what the machine is to achieve, and then structuring the payments in such a way that the developer of the technology only makes a profit if the performance specifications are reached the interests of both parties are protected and the technology developed meets real world needs.

Since its conception 19 years ago, the tea harvester has been continually improved. New materials, like polyurethane, have been incorporated into its design.

Mistakes have been made, but have lead to a better product (for example, on the first T5000 machines, the hydraulic motors failed, leading to the use of different, more reliable motors).

By responding rapidly in the commissioning phase to unusual demands that users have placed on their machines, most of the Williames Hi-Tech harvesters produced in the last eighteen years are still running today.

Developing new technology can be a very frustrating process. There is no previous experience to draw on, and the machine has to meet the performance specifications.

For example, during the development of the tea harvester, Williames' have had to organise an emergency shipment of hydraulic motors for six machines into the African bush. The motors being used failed two weeks into their trial since they didn't perfor m to their supplier's specifications, because of the particularly rugged demands placed on them by operators.

Other examples include the need to invest heavily in designing tea cutter bars which deliver optimal performance at high speed operation; the need to develop a range of fabrication and design techniques to counter unusual weld-fatigue problems in highl y-stressed components; and the need to rescue a worker in Papua New Guinea who accidentally went to sleep inside a rotary valve. The valve ended up bent, and the worker just a little bruised!

During the initial phase of developing a machine, many problems such as those outlined above cannot be anticipated.

Only by reacting quickly and by continually making improvements has WHTI had commercial success with the tea harvester.

During its life, Williames Hi-Tech International has gradually developed a Performance-Driven Design and Development Department, which is now located apart from its main manufacturing factory.

Anyone interested in harnessing the services of this department should contact Bruce Rowse at Williames Hi-Tech International (at the address above).

Contact: Dr Rob Fletcher, School of Land and Food, The University of Queensland Gatton College, 4345; Telephone: 07 5460 1311 or 07 5460 1301; Facsimile: 07 5460 1112; International facsimile: 61 7 5460 1112; Email: r.fletcher@mailbox.uq.edu.au

[New Crops Home Page] [New Crops Program] [Australian New Crops Newsletter] [New Crops Publications] [Order Form] [People] [Crop Profiles] [Other Resources]

originally created by: GK; latest update 6 June 1999 by: RF